About 30 whales are trapped in the shallow water near Everglades National Park, and about 10 whales are beached on the park’s shore, Reuters reported. Four of the beached whales have died, the news agency said.

The mass stranding, in one of the park's remotest regions, was first discovered on Tuesday afternoon, and rescue workers from the park and the National Oceanic and Atmospheric Administration (NOAA) have since then been attempting to keep the whales stable until high tide returns, NBC 6 Florida said. A spokeswoman for the park told CNN that the pilot whales likely became trapped in the shallow water when high tide receded. Rescue workers hope that the whales will be able to swim back to deep water as the tide comes in, CNN said.

Pilot whales, a member of the dolphin family (as are killer whales), are found throughout the world’s oceans, in both the northern and southern hemispheres, and are numerous in the Gulf of Mexico. The whales are highly social animals and tend to travel in pods of some 20 to 90 companions.

Pilot whale beaching is common, for reasons that are still unclear but that could be related to social dynamics within the species' tight-knit pods, according to NOAA. In the largest pilot whale stranding ever reported, 450 pilot whales were trapped in a bay off of New Zealand’s Great Barrier Island in 1985. New Zealand and Tasmania have the bulk of all pilot whale stranding incidents worldwide.

The last mass stranding of pilot whales in southwest Florida was in 1995, according to NOAA.